So impressive was ancient Egypt's building efforts over the pharaonic period that it commanded two wonders of the ancient world. One, the  Great Pyramid of Giza, was built near the beginning of Egyptian history, while the second, Seventh Wonder was mostly built by one of Egypt's last pharaohs,  Ptolemy I Sorter, though he died prior to its completion. While the first still stands, the latter was destroyed, almost certainly by an earthquake. This was Pharos Lighthouse of Alexandria, which of the vanished wonders of the ancient world, was the last built and the last to remain standing. Pharos Lighthouse stood on the eastern point of Pharos Island some distance from the city center of Alexandria. Constructed at the beginning of the third century BC over a period of about twelve years and at an enormous cost and using considerable slave labor, Pharos Lighthouse was completed and inaugurated by the first Ptolemy's son, Ptolemy Philadelphus, in 283 (some say 279 BC, when Ptolemy Philadelphus held a festival to honor his parents). Prior to its destruction, it underwent a number of modifications by later rulers. The architect was Sostratos, a Greek from the Asia Minor city of Cnidus, whose name also appears on the sanctuary of Appolo at Delphi and on Delos. Though only the king's name was allowed on buildings erected during their reigns in the period, Sostratos got around this by also carving his own with a dedication, which was then covered with plaster. The consecration in honor of Ptolemy was then carved into the plaster, which over time peeled Mosaic in St. Mark's basilica representing the saint arriving in Alexandria, showing the Pharos Lighthouse still standing and in use away leaving only Sostratos dedication, which provides, "Sostratos of Cnidus, son of Dexiphanes, to the savior gods, for sailors. The lighthouse was apparently a tourist attraction from the very beginning. We are told that food was sold to visitors at the observation platform at the top of the first level. A smaller balcony provided a view from the top of the eight-sided tower for those that wanted to make the additional climb. The view from there must have been impressive as it was probably 300 feet above the sea. There were few places in the ancient world where a person could ascend a man-made tower to get such a perspective. The lighthouse was approached first through the Heptastadion at the entrance to Alexandria's harbor. The Heptastadion was a solid granite wall that extended the length of seven stadiums and connected the city with Pharos Island. One of Hermann Thierch's drawings of the Pharos LighthouseMuch of what we know about the structure of the lighthouse comes from a German scholar named Hermann Thiersch, who authored a book on the topic that remains one of the best reference works on Pharos Lighthouse to this day. There was no real lack of representations of the Lighthouse for Hermann Thiersch to use in his studies of the structure, for it was depicted on coins, mosaics and small models of it were also available. While all of these agree as to the building's basic design, none provide much detail.  On the other hand, there is a surprising lack of descriptions by ancient writers and in fact most come from Arab travelers. Many of these, however, combine precise details mixed with wild fantasies. While they provide some good information on the lower levels of the tower, they provide little valuable information about the upper levels and almost nothing concerning the light source. In fact, by the medieval period the upper section had already been destroyed. However, some of their accounts are interesting. Ancient travelers speak, sometimes of a mirror and sometimes even of a huge lens designed to increase the range and visibility of the light, but these descriptions frequently come from travelers who visited the structure after the top section was already lost.  One story states that this mirror used in the beacon could be used as a weapon to concentrate the sun and set enemy ships ablaze as they approached. Another tale says that it was possible to use the mirror to magnify the image of the city of Constantinople from far across the sea to observe what was going on there. Both of these stories seem implausible, though. A Moorish geographer from Spain, Idrisi, who visited the tower in 1115 AD, was so impressed with the structure that he numbered all of its stairs and measured the height of its balconies, bazaars and tower. Fifty years later, another Morrish scholar, undertook an examination of the tower and tells us that the base tier rested on massive blocks of red granite and that the blocks were joined not by mortar but by molten lead so as to reinforce the structure against the heavy pounding of the sea. Pharos Lighthouse is consistently depicted and recorded as being a monumental edifice with three tiers, consisting of a lower quadrangular one, surmounted by an octagonal layer and topped by a cylindrical section. The approach to its entrance was by way of a long ramp with vaulted arcades. Within, an apparently large spiral ramp led to some fifty service rooms and also allowed pack animals to bring firewood up to the third tier to feed the fire that acted as the light source. According to the Moorish travelers, the building was 300 cubits high. Because the cubit measurement varied from place to place, this could mean that the Pharos stood anywhere from 450 to 600 feet in height, although the lower figure is more likely. Some modern interpretations of these measurements provide that the lowest square, measured about 55.9 m (183.4 ft) high with a cylindrical core; the middle octagonal with a side length of 18.30 m (60.0 ft) and a height of 27.45 m (90.1 ft); and the third circular 7.30 m (24.0 ft) high. The total height of the building including the foundation base was about 117 m (384 ft), equivalent to a 40-story modern building. A bronze coin of the second century depicting Isis Pharia holding a sail in front of the Pharos LighthouseSupposedly, the light from the tower could be seen from almost 100 miles out to sea, though this seems a little far fetched. Even Thiersch's work is suspect, with a hot fire burning beneath a copula supported on columns. One must wonder how the stonework would not crack under the heat of a constant fire. Yet, in several texts a statue is mentioned that surmounted the lighthouse and from a poet named Poseidippos of Pella, who lived in Alexandria during the third century BC, we learn that this statue almost certainly depicted Zeus the Savior, though he may have been accompanied by Poseidon, the lord of the waves.  However, others have suggested that two statues depicted the Dioscuri, who were the twin sons of Zeus and Leda and protectors of seafarers. In fact, a gem which has recently been examined suggests that in fact the beacon on the lighthouse may have been open and the statue, or perhaps a number of statues may not have surmounted the building but stood on a lower level. An engraving of the Pharos by Monneret de Villard, showing the Lighthouse as it stood during the Arab period. Note that the base resembles that of the future Fort Qait BeyIrregardless of the beacon and statues, many scholars now believe that the lighthouse did not take on a purely Greek style, as it has so often been portrayed. The Ptolemies mixed their own culture with that of the Egyptians, and in building the lighthouse, it is now believed that they probably borrowed from the pharaonic tradition, using Egyptian stone, though the stone may have been covered in white marble. It must have been a very solid building, for it survived for nearly two millennia (until the fourteenth century AD), making the better of violent storms and even large titles waves, such as one that affected the eastern Mediterranean in 365 AD. Only earthquakes finally got the better of it. Between 320 and 1303 AD, there were twenty-two earthquakes that shook Alexandria that were severe enough to be mentioned by ancient writers. During this period, we have considerable records regarding the structure's life. In 796, the lighthouse may have lost its upper tier, which apparently went without repair for about a century. We are told that afterwards, Sultan Ibn Tulun (868-884) built a mosque with a dome in its place. However, this seems to conflict with Idrisi's report that the structure still operated as a lighthouse in his visit in 1115 AD. The account of this mosque may come from an unlikely tale that part of the lighthouse was demolished through trickery. The story goes that in 850 AD, the Emperor of Constantinople, a rival port, devised a clever plot to get rid of the Pharos. He spread rumors that buried under the lighthouse was a fabulous treasure. The caliph supposedly ordered the building to be torn down, and as the Arab workers began dismantling the cylindrical tower, the huge mirror of polished metal slipped away from its base and crashed into the sea. The Well of Wonders: The Pharos of Alexandria, a fresco by Nicolas Schiel created in 1669The beacon chamber was then stripped down as well as the eight-sided middle section and its two balconies. With only the base of the Lighthouse remaining, the caliph realized that he had been tricked and halted further destruction. He then ordered his workmen to start rebuilding the tower, but since the damage was now too extensive, the project had to be abandoned and instead of a tower, a crude mosque was constructed. Idrisi's report appears to completely negate this tale, though there are a number of reports of such a mosque surmounting the second tier. In 950 and again in 956, parts of its surface cracked and to stabilize it, the lighthouse was reduced by some 22 meters in height. In 1272, the famous Sultan, Salah el-Din (Saladin) undertook restoration work, but alas, his work was in vain because on August 8th, 1303, a major earthquake shook the whole eastern Mediterranean. This was to be the end of the A terracottal lantern made during the Ptolemaic period representing Pharos LighthouseSeventh Wonder of the ancient world, as attested to by a maritime map preserved at Montepellier that dates the quake and notes that the lighthouse was totally destroyed. Actually, there remained some ruins of the structure for decades to come. A traveler named Ibn Battuta visited Alexandria twice, once in 1329 and again in 1346. In the first visit, he was still able to climb the ramp and reach the door of the tower, but on the second visit, the lighthouse was in such ruins that he could no longer get near it. These ruins remained for just over a century, until the Mamluk sultan Qait Bey finally had them cleared away in order to construct his fort which still stands there today. Supposedly, it uses some of the stone blocks form the Lighthouse in its walls. However, the story of Pharos Lighthouse does not end here. In 1962, a young diver searching for fish at a depth of 24 feet, spotted fragments of an immense statue, one piece alone measuring more than 20 feet in length. Egyptian naval divers, together with expert from Alexandria's Greco-Roman Museum were summoned to the area and verified the young man's report, concluding that the sculpture was a fragment of the colossal statue of Poseidon. Then, in the fall of 1994, a team of archaeological scuba divers under the direction of Jean-Yves Empereur, also located very large blocks of stone that are believed to have been a part of the lighthouse, though there is a profusion of objects superposed from different periods. Some of this material came from structures in the Nile Delta and from Heliopolis and may have been used in the lighthouse, though there is a growing notion that the Pharos might have been a part of a greater complex with both civic and religious functions. However, it is known that, after the Cypriot king, Pierre I de Lusignan, sacked Alexandria over two days in 1365, the Mamluk rulers of Egypt attempted to block the entry to the eastern harbor by jettisoning rubble from the crumbling ancient city. This fact might have provided a partial explanation for the wealth of remains lying in this patch of sea but it was not sufficient to account for the presence of certain massive blocks weighing between 50 and 75 tons. Furthermore, the disposition of the largest blocks, running in a north-easterly line from the foot of the fort, firmly suggested a monument of considerable size and height falling in to the sea. This has convinced researchers that they have indeed found the remains of the lighthouse. Some of the remains, including sphinxes, columns, capitals, colossi and fragments of inscribed obelisks, together with two massive segments of the lighthouse, are now on exhibit in an open-air museum near Kom el-Dikka in Alexandria. So far, some 2250 blocks have been plotted and archaeologists believe there are at least 500 more to be registered. Though many issues surrounding Pharos Lighthouse remain mysteries, perhaps someday we will have a much more complete understanding of this Seventh Wonder of the ancient world.